Software as a service (SaaS) is a technique for distributing and marketing software as a subscription-based service. Rather than load software onto a laptop or personal computer, the user subscribes to software that is hosted in a central location, often termed the cloud. SaaS gained popularity with database and management software or high cost software with low frequency usages such as computer aided design, however, nearly any type of software is now available through SaaS, including word processing, spreadsheets and even operating systems.
One drawback to SaaS is that another layer of authentication is added to the user's daily routine. A user may turn on a laptop then log into the laptop, the local area network or wireless network, then be prompted for authentication again every time SaaS is accessed. Techniques have been proposed in which a user gains access to multiple services after providing credentials only once. However, these techniques leave security holes in certain scenarios.